Past the last San Francisco streetlight, past the toll plaza and the vista-point pullout where tourists aim their phones at the bridge, there is a gate on a one-lane road that most people driving by have never noticed. Open it — the combination changes by season, and the Marin Headlands rangers post it on Recreation.gov when you book one of the four campsites — and the road drops through a canopy of eucalyptus and Monterey cypress so thick that the bridge disappears entirely. At the bottom, maybe a mile in, is Kirby Cove: a small pocket of sand, a fire ring, the sound of the bay against rock, and almost no one.

The cove sits technically outside San Francisco city limits, in the Golden Gate National Recreation Area, but it functions as the city's least-visited backyard. On a clear afternoon you can see the bridge towers from the waterline, the traffic across them audible as a low hum, and the Marin hills rising behind you. It costs twelve dollars a night to camp. Most evenings, the loudest thing is the fog signal on Point Bonita.

Getting a reservation requires more planning than most city beaches demand — the sites open up on a rolling 90-day window and move quickly on spring weekends — but show up on a Tuesday in October and you might have the whole cove. A few people arrive by bicycle, threading the Conzelman Road descent in the dark, headlights catching the hairpin turns. Most come by car, park at the top, and carry their gear down on foot.

The beach itself is narrow and pebbly at high tide, wider and sandier when the water pulls back. There are no facilities beyond a pit toilet and a food locker at each site. The fire rings fill up with driftwood by evening.

Tomorrow, if you drove to the vista point and looked down the hill, you'd see the gate. It blends into the trees. Most people keep driving.